• International Journal of Railway
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• 제2권3호
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• pp.107-112
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• 2009

Research projects of SNCF aim at reducing the costs of infrastructure possessions and improving the operational equipment availability and safety. This permanent search for a better regularity led the SNCF to analyse the maintenance approach of signalling equipment in detail. Until now, it was commonly acknowledged that signalling equipment, which consists of many electronic devices, is not subject to aging. In this study, a Weibull lifetime model, able to describe an aging phenomenon, is used and it can be shown that the deterioration is statistically significant. The validity of the model is tested. We also analyse the influence of environmental covariates. We simulate different scenarios in order to investigate the impact of several maintenance strategies as well as on future maintenance costs, on the amount of components to replace based on the mean age of the network. It can be shown that in most cases a systematic replacement strategy offers the best solution.

• 전기학회논문지
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• 제61권9호
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• pp.1221-1225
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• 2012

This paper describes CSC(Current Sourced Converters)-based HVDC operational strategy for voltage stability enhancement in the power system. In case of CSC-based HVDC system, rectifier and inverter consume reactive power up to about 60% of converter rating. Therefore, CSC-based HVDC is basically not useful system for voltage stability even if AC filters and shunt capacitors are attached. But, If the particular power system condition is fulfilled, CSC-based HVDC also can be the rapid reactive power source for voltage stability enhancement using a cooperative control with converter and AC filters/Shunt Capacitors. In this paper, the cooperative control algorithm is presented and simulated to ${\pm}80kV$ 60MW HVDC system in Jeju island.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.163-165
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• 2007

Generally, the power management system of fuel cell hybrid vehicle (FCHV) requires a unidirectional DC/DC converter for the fuel cell (FC) and a bidirectional DC/DC converter for the battery. To manage the various power flows between these modules with a simple way, a new band-gap reference voltage (BGRV) control strategy is proposed. The proposed method easily controls this variable power flow by setting the reference voltages of each converter to slightly different values, and it can be simply implemented by commercial controllers as well. The operational principle of proposed method is presented and verified experimentally by the 400W prototype.

• 한국건축시공학회지
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• 제9권5호
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• pp.163-172
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• 2009

고객의 중요성이 지속적으로 증대됨에 따라 조직 구조를 고객 중심 구조로 전환해야 한다는 요구가 증대되고 있다. 건설업은 제조업과는 달리 비 반복적이고 비표준화의 업무특성을 가지고 있으므로 하나의 건축물을 완성하기 위하여 다양한 자재, 인력, 기술, 장비 등을 투입하여 복합적인 업무를 수행하게 된다. 따라서 이러한 업무를 추진하는데 있어서 예기치 못했던 상황들은 쉽게 발생하기 마련이다. 본 연구의 목적은 비용 관리 및 브랜드 관리를 통하여 공동주택 상품의 고객서비스를 개선하기 위한 전략을 연구하는 것이다. 본 연구를 위해 공동주택을 중심으로 고객서비스 및 경영전략에 대한 경영학적 정의와 개념을 정리하고, 문제점 분석을 위하여 주택 입주 고객과 전문가집단을 대상으로 설문조사를 실시한다. 또한 국내 주요 건설 회사들의 외부 환경 및 내부 역량을 분석하고, 고객서비스의 시장상황을 반영하여 SWOT 분석을 실행한다. 이를 통하여 기간별 전략 추진계획을 세우며, 전략추진 경영자원을 분석하여 전략의 성과를 예측한다.

• Strategy21
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• 통권39호
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• pp.47-81
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• 2016

This paper has attempted to examine the political and operational contexts within which North Korea's latest acts of nuclear blackmail, its test-firing of an SLBM on April 23rd 2016 and its fourth nuclear test on January 6^th 2016, should be understood. Analysis of the KN-11 SLBM and the Sinpo-class SSB is based on official South Korean, US and others sources, especially the ROK MND, as well as other resources from South Korea, US and others. Unfortunately, the results of this exploration are inconclusive: there is simply not enough evidence available at present to either confirm or refute the existence of a functional North Korean SLBM and SSB. Nevertheless, the North Korean determination to possess such assets should not be taken lightly. But even accepting North Korea's claims about its SLBMs at face value, which is undermined by news of apparently unsuccessful follow-up test-firings in November, and probably December 2015, there is little proof that North Korea has yet succeeded in miniaturizing its nuclear warhead, so the most extravagant fears are not yet justified. Taken together with North Korea's latest announcement of a supposed successful SLBM ejection-test, on March 23^th 2016, the KN-11 SLBM claims should probably be seen as primarily about proving North Korea's status as a nuclear power, both to exert external political pressure and to bolster internal political support for Kim Jong-un's rule. In conclusion, this paper recommends formulating a preemptive anti-access strategy for the ROKN, proposes acquiring an ASW CV and SSNs to implement submarine strategic deterrent patrols, and urges extending the existing limited AORs to facilitate the preemptive anti-access strategy. Other deterrence options may be suggested, but it is surely significant that the ROKN has recently publically referred to the deployment of an ASW CV and SSNs for the first time.

• 한국산업정보학회논문지
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• 제19권1호
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• pp.99-109
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• 2014

본 연구에서는 개방형 혁신을 추구하고 있는 기업 중 스마트폰 제조업체이면서 앱스토어를 직접 운영 중에 있는 애플과 삼성전자를 대상으로 IISIn model을 이용하여 플랫폼 전략을 분석 비교하였다. 앱스토어의 선도 기업인 애플은 플랫폼의 질적 강화 및 고객 충성도를 높이고 플랫폼 통제권 강화를 위해 폐쇄전략을, 반면에 후발 주자인 삼성전자는 플랫폼의 네트워크 효과 및 선순환 구조의 정착을 위해 개방형 전략을 실시 중이다. 연구 결과 지속적인 선순환 구조가 이루어지기 위해서는 우수한 플랫폼 환경과 더불어 참여자들의 자유로운 진입인 '개방'과 창출된 가치의 '공유'가 보장된 플랫폼 전략을 실시하여야 할 것으로 보인다. 본 연구는 학문적으로 IISIn model을 통하여 애플과 삼성전자의 개방형 혁신 플랫폼을 최초로 비교 분석한 연구하였다는 기여점이 있고, 실무적 측면에서는 후발기업의 개방형 혁신 플랫폼 전략수립에 도움을 줄 수 있을 것으로 기대된다.

• International Journal of Internet, Broadcasting and Communication
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• 제8권2호
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• pp.1-22
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• 2016

While many organizations believe that cloud computing has the potential to reduce operational cost by abstracting capital assets like data storage center and processing systems into a readily on demand available and affordable operating expenses, still many of these organizations are not aware of the factors determining the performance of cloud computing technology. This paper provides a systematic literature review focusing on the factors determining the performance of cloud computing. In trying to come up with this review, the following sources were searched for relevant articles: ScienceDirect, Scientific.Net, ACMDigital Library, IEEE Xplore, Springer, World Scientific Journal, Wiley Online Library, Academic Search Premier (via EBSCOHost) and EdITLib (Education & Information Technology Digital Library). In first search strategy, approximately 100 keywords related to the research domain like; "Cloud Computing" and "Cloud Services" were used. In second search strategy, 65 keywords more related to the research domain were selected. In the third search strategy, the primary materials were identified and classified according to the paper types (Journal or Conference), year of publication and so on. Based on this study, twenty (20) factors were found that determine the performance of cloud computing. The IT organization needs to consider these twenty (20) factors in order to adopt cloud computing.

• Educational Technology International
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• 제11권1호
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• pp.47-68
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• 2010

The purpose of this study was to analyze majors trends and issues of e-Learning curriculum for human resource development in the corporate context. The e-Learning curriculum was chosen as the subject of research consists of 2,710 lectures that were given from 2007 to July 2009 for the recent three years by providing at Ministry of Labor and Korea Research Institute for Vocational Education & Training. In order to investigate trends and issues, it was employed theme analysis which is one of the types of document analysis that approach a qualitative research methodology. As a result of this research, 7 major trends and issues in e-Learning curriculum for HRD in the field of corporate education were drawn; ① Strengthening expertise through learning of job related professional knowledge, ② Cultivation of common & essential knowledge for a job to increase work performance efficiency ③ Organizational management strategy for improving performance, ④ Organizational management and operational strategy for actively responding to environmental changes, ⑤ Leadership as a strategy for cultivating core personnel and field-centered practical leadership. ⑥ Creating a happy workplace through the work-life balance, ⑦ Strengthening global communication skill. Based on these analysis, practicals and theoretical implications of e-Learning professionals and HR researchers for HRD were suggested.

• Journal of Astronomy and Space Sciences
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• 제32권4호
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• pp.411-417
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• 2015

Several optical monitoring strategies by a ground-based telescope to protect a Geostationary Earth Orbit (GEO) satellite from collisions with close approaching objects were investigated. Geostationary Transfer Orbit (GTO) objects, Inclined GeoSynchronous Orbit (IGSO) objects, and drifted GEO objects forced by natural perturbations are hazardous to operational GEO satellites regarding issues related to close approaches. The status of these objects was analyzed on the basis of their orbital characteristics in Two-Line Element (TLE) data from the Joint Space Operation Center (JSpOC). We confirmed the conjunction probability with all catalogued objects for the domestic operational GEO satellite, Communication, Ocean and Meteorological Satellite (COMS) using the Conjunction Analysis Tools by Analytical Graphics, Inc (AGI). The longitudinal drift rates of GeoSynchronous Orbit (GSO) objects were calculated, with an analytic method and they were confirmed using the Systems Tool Kit by AGI. The required monitoring area was determined from the expected drift duration and inclination of the simulated target. The optical monitoring strategy for the target area was analyzed through the orbit determination accuracy. For this purpose, the close approach of Russian satellite Raduga 1-7 to Korean COMS in 2011 was selected.

• 한국응용곤충학회지
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• 제31권3호
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• pp.314-327
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• 1992

Insecticide resistance is a serious is a serious threat to IPM, resulting in various adverse effects not to mention the loss of yield in agriculture. One approach to counter the problem is the disruption of resistance mechanisms. This can be achieved by (1) compounds which show a negative correlation with resistance at the site of action, (2) specific metabolic inhibitors which serve as synergists, or (3) a certain combination of two insecticides producing a joint action. This approach, however, requires certain precautions for the side effects may cause an increase in toxicity to mammals. Owing to the recent advances in theoretical studies on resistance management employing computer simulation and mathematical models, a few principles to reduce the risk of development of resistance have been clarified. They are helpful in designing operational strategies with regard to, for instance, insecticide doses to be applied, mode of application, and choice and nature of the insecticide(s) to be used. For restoration of insecticide susceptibility of a resistant population, reintroduction of susceptible individuals to the resistant population is feasible when certain conditions are met. Natural enemies which developed resistance to insecticides can be an important component of IPM as has been shown in the pest management in apple orchards. After all, the implementation of a successful resistance management program depends upon cooperation between different sigments of the agricutural community. Although resistance is a preadaptive phenomenon, in some cases spontaneous loss of resistance does occur without contamination by susceptible individuals. The instability of resistance in these insects implies the possible existence of a switch machanism controlling the expression of resistance gene(s). Elucidation of such a mechanism may eventually provide us with a new technical approach with which we can combat the problem of insecticide resistance.